Cotton pellet-induced granuloma

The chronic anti-inflammatory activities of apigenin were evaluated using cotton pellet-induced granuloma according to the method of Winter and Porter.29 Sterile cotton pellets, weighing 10 mg, were implanted subcutaneously, under light ether anesthesia, into axillary region, in each rat. Animal grouping as well as apigenin and diclofenac dosing was done as previously described; all drugs were given daily for seven consecutive days from the day of cotton pellet implantation. On the eighth day, the animals were anaesthetized, and the pellets together with the granuloma tissues were carefully excised and made free from the surrounding tissues. The wet pellets were weighed, and then dried in an incubator at 60°C for two hours until a constant weight obtained, after that the dried pellets were weighed again. The exudate amount (mg) was calculated by deducting the constant dry weight from the immediate wet weight of the pellet. The granulation tissue formation (dry weight of granuloma) was calculated after subtracting the weight of cotton pellet (1 mg) from the constant dry weight of pellet and taken as a measure of granuloma tissue formation. The percent inhibitions of exudate and granuloma tissue formation were calculated.